Flotation-machine



L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

Patented Sept. 6, 1921.

4 SHEETS-SHEET w m WWW m w; m x n \N AC. Q m Q N @W Q E V 1\\ Hr v m J Ji Q El \w l \w dr N w fimmw M L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

1,389,674. PatentedSept. 6,1921.

4 SHEETS-SHEET 2.

INVENTORS l. 0. 17006;

L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED $251920.

L. D. LYONS AND C. F. HOFF.

FLOTATION MACHINE.

APPLICATION FILED MAY 21, 1920.

1,389,674. PatentedSept. 6, 1921.

4 SHEETSSHEET 4.

[ir a UNITED STATES PATENT OFFICE.

LEO DANIEL LYONB AND CONRAD FRANCIS HOFF, OF BUTTE, MONTANA.

FLOTATION-MAGHINE.

Application filed Kay 21,

tana, have invented a new and Im roved Flotation-Machine, of which thefol owing is a full, clear, and exact description.

This invention relates to means for recovering valuable minerals fromtheir crushed ores by the flotation process, and has referencemoreaparticularly to a machine which is equippe with floating frothcutters, and an automatically controlled weir gate.

As commonly ractised in the recovery of valuable minera s, the orecontaining the minerals is crushed to a suitable fineness,

and is introduced into a chamber where it is agitated with water to forma pulp, and a small percentage of oil and acid is added with theintroduction of air during the agitation. A froth is formed, as aresult, which consists in a large mass of air bubbles which rise to thesurface carrying with it the valuable minerals contained in the crushedore, and leaving behind the worthless gangue. This process isespeciallyadapted for min erals of'the sulfid type where the preferential actionof the air bubbles on the valuable minerals contained in the pulp isespecially marked and causes a very complete separation of said valuableminerals from the worthless gangue.

It is a known fact that in order to accomplish the very best separation,it is necessary to remove the froth containing the concentratedminerals, from the spitzkastens practicall as fast as it is formed,since the air bubb es are fragile, and unless quickly re moved willbreak and drop the valuable minerals back into the pulp. In order toaccomplish this, the pulp level in the spitzkastens in the flotationmachine 'must' be maintained very close to the froth discharge level. Itis diflicult to maintain the pulp 7 level in the 'spitzkastens at such apoint where the maximum volume of froth will be skimmed ofi properly,and it is evident that any ofthe pulp level ,in the spitzkastensSpecification of Letters Patent.

Patented Sept. 6, 1921 1920. Serial No. 383,229.

above that of the normal operating pulp level will result in the S10ping of the gen ue material over with t e concentrate froti into theconcentrate launder. Special types of mechanical Skimmers have been usedto remove the froth as it is formed, but these Skimmers increase theslopping of the gangue material, since when the skimmer paddle strikesthe pulp it throws some over into the froth of the concentrate launder.Some machines are provided with a middling launder built parallel to theconcentrate launder, and extending the full length of the machine.Aprons are provided from the lips of the spitzkastens to the outer sideof the middling launder, which extend the full width of thespitzkastens. When the machine is operating normally, the froth isskimmed off by means of the mechanical skimmer, and discharges over theapron into the concentrate launder; but when slopping occurs, the apronsare removed so that the concentrate froth and the gangue pulp are sentdirectly to the middling launder which leads to the feed end of themachine. It is evident that the above provision, while it does serve toprevent gangue from slopping into the concentrate launder (at times onlyhowever when the operator of a machine is present to remove thenecessary aprons) is a poor practice, since the concentrate froth is notsent to the concentrate launder, but is returned through the middlinglaunder to the feed end of the machine to be re-worked. This greatlydecreases the efficiency of the machine, since the mineral load in themachine is greatly increased by re-working so much material.Furthermore, when a concentrate is returned to the feed end of themachine, not as complete separation is obtained on re-working, since itis found that the gangue pulp tends to hinder the selective andpreferential action of the air bubbles. This is especiall noticed when aroughing machine is use to be followed by a finishing machine reworkingthe concentrate. When a sloppy, rougher concentrate froth is made, it ispossible to make th'm froth fairly clean and free from gangue byexcessively banking the cleaner machine used for the fine concentration,but to-excessively bank (deep bed of froth hence low pulp level) willcause the tailing of the machine to have a high percentage of valuableminerals due to the bursting of the air bubbles which allows theminerals to settle into the gangue material. It often happens that whenbanking is resorted to, the operator is deceived regarding the depth ofthe froth in the machine, so that the loss of valuable minerals in thetailings of the machine will be excessive.

V In some flotation plants, the flotation feeds vary in volume so thatexcess occurs at the lip of the first spitzkasten, and within a shortperiod, unless a correction is made, there is an excessive overflow inall the Spitzlrastens of the machine, so that much gangue accomplishedby' opening a valve in the tailing spitzkastens.

An object of this invention therefore is to .provide a floating frothcutter at the lip of each spitzkasten which willalways remove a definitedepth of concentratev froth, regai'dless of the pulp level in thespitzkasten, which may vary due to variations in the volume of the pulpfed into the first spitz hasten. I

Another object of this invention is to provide a means of by-passing anyexcessive overflow in any spitzlrasten to the adjacent spit'lzkasten sothat the pulp level will be maintained substantially constant. 7

Another object of this invention is to provide an automatic means forraising and lowering the weir gate in the last spitzkasten whenvariations in. the volume of pulp level will be feed occur, so that themaintained constant.

Another object of this invention is to pro vide means of lay-passing thepulp around one cell when same 18 out of order.

A further ob ect ofthis invention, is to provide a flotation machinewhich will make a cleaner concentrate, a tailing containing a lowerpercentageofvaluable niine'als, and which will have a lowerconsumptionof oil u o acid or alkali.

A still further object of this invention istofprovide a'inachine whichwill not require mechanical shimmers, and which will recation, in whichit is understood that the drawings illustrate only one form of theinvention, and in which- Figure 1 isa' side elevation of the flotationmachine with parts broken away to disclose the construction.

Fig. 2 is a plan view -chine. Fig. 3 is a section through. the machineon the line 3-3 of Fig. 1.

' Fig. 4 is a section through the machine on the line 4l4t of Fig. 1. p

1* ,5 is a section through the machine on thelines 5-5of Fig.1. r

Fig. 6 is a transverse sectional view on a of the flotation malarge salethrough part of one cell of the flotation machine. Fig. 7 is a sectionon a large scale througl a cll on the line 7 of Fig. 6.

Fig. 8 is a sectional view on a large scale through one of the removableoverflow par titions. i

Fig. 9 is a plan view on a large scale of one of the floating frothcutters.

Fig. 10 is a: sectional view through the a 11 isa diagrainmaticalperspective" view of thesystem of operating leverscon froth cutter onthe line l0-10 of Fig. 9.

trolling the Weir gate.

Referring to the accompanying drawings by numerals, 10 indicates thefront oblique wall of a spitzkastemhaving a second vertical wall 11,and'side walls 12. These walls 7 of the cell form what is ordinarilycalled a spitzkasten, and the oblique wall 10 has a lip 13 at its upperedge, whose purpose will be hereinafter described. v

A bottom 14 is formed in the spitzkasten, and a: false bottom 15 issecured between the walls thereof at some distance above the bottom 14.A number of the spitzkasten's' are joined together in series, so thatthe side walls 12 of one also form the side walls for adjacentspitzkastens.

A rectangular agitating chamber 16 having a bottom 17 is secured to theside wall empties into saidagitating chamber 16 at a point nearits top.The agitating chamber 16' is lined at its bottom with a rectangular box19, and a port 20 is provided in the wall 11 and the adjacent wall ofthe'box 19, which opens into the spitzkasten. The agitating 11 of eachspitzkasten, and an intake pipe 18 chamber 16 is supported by anysuitable V frame-work 21, and. vertical standards 22 are also supportedby said frame-worlnsaid standards being provided at their upper;

ends with ayoke 23 which may preferably be of cast metal, and whichsupports a horizontal shaft 2 1 extending across all the 7 mixed withair.

aire on thepulp 44.

' la r to the propeller of a power driven boat.

. each of the vertical shafts by beveled gears not shown.

As the finely pulverized ore, mixed with water, a small percentage ofoil and acid to form a pnlpfis introduced throuph the pipe 18, it isagitaterhgyl the impel er 26 and downwardly a ja'cent theport 20 so asto deflect the aerated ulp from the chamber 16 to thebottom of thespitzkasten, so as to leave the froth which rises tothe surface of thepulp into the spitzkasten, undisturbed.

A concentrate launder 28 extends along each of the s itzkastens,adjacent the lips 13,

and slopes o liquely to the delivery end of the machine, where itempties into a pipe 29 which receives the concentrate froth containingthewaluable minerals. The launder ,-.28 hasan 0utside-wall30, and aninside wall 31, which also forms the wall of, the middling launder 32,having an inside wall 33. The middling launder 32 slopes obliquely fromeach end of the machine to'the center thereof, where it empties into apipe 34 extending. below the machine, and t0 the other side, where it'isconnected to a bucket elevator 35 delivering to a pipe 36, which isconnected to the pipe 18. The insidewall' down-take pipes 38 areconnected to the launder 37 and'to a compartment 39 formed by the falsebottom 15. An apron 40 extends obliquely from the wall 33 to the wall31, and a plurality of slots 41 are formed in 1 the wall 33fadjabentsaid apron so as to connect thelalinder-37 with the launder 32.

The froth which forms on top of the pulp in the spitakastenis composedof concentrate frp'th 42, belowwhich is asub-froth 43 sup- Theconcentrate frotlt 42 contains most of the valuable minerals (usuallyiii-the sulfid form) with very little gaiigue material. The top of the.wal 33'is spaced apart from the lip l3 of the spitzkiasten, and acutting apron 45 is hinged on abrack'et 46, which is secured to the wall33.atl.'the junction of the apron 40 with said w .33.

eapron 45 has horizontal supports 47 to are attached a plurality(preferably two .(in number of metallic hollow floats 48, which areadjustably secured theretqby means of nuts 49 so that the position ofthe supports 47 relative to said e aerated pulp flows through the port20 into the spitz kasten, where it rises 'on the false bottom 15 tothelevel of the li 13. A "shield, 27 extends floats may be varied Thus,as seen in Fig. 6 the floats 48 will be so adjusted and the supportswill be so positioned that the apron 45 will act as a cutter to separatethe concentrate froth from the sub-froth so that the concentrate frothwill pass over the apron 45 into the concentrate launder 28, while thesub-froth 43 will pass between the walls 33 and 10 into the firstmiddling launder 37.

The Sub-froth will flow from the first middling launder 37 through thedowntako pipe 38 into the compartment 39. If desired, a perforated pipe37 (Fig. 4) may be positioned in the launder 37 which is adapted todirect a spray of water on the subfroth in said launder so that saidsubfroth will be broken up. If the flow of the sub-froth 43 becomes toogreat to be handled by the down-take pipe 38 in spite of the waterspray, the excess will flow through the slots 41 into the middlinglaunder 32, which will conduct it through the pipe 34, the bucketelevator 35, the pipe 36 and the pipe 18 back into the agitating chamber16 of the first cell. The pipe 50 connects the chamber 39 with thechamber 16, and the up or end of said pipe is positioned directly un erthe impeller 26 so that when said impeller is rotated in the properdirection it will draw the material from the compartment 39 into thechamber 16 where it will be further aerated.

A weir 51 is provided in each of the spitzkastens (Fig. 1) and isconnected at. its lower edge to the false bottom 15, while its upperedge is positioned somewhat below the lip 13 of the spitzkasten.- Theconcentrate froth is prevented from flowing over the weir 51 by a shield52 which is connected to the wall 12' of the spitzkasten by endwal'ls53. The pulp flowing over the weir 51 is substantially free from airbubbles, since it has been taken from the bottom of the spitzkasten, andsaid pulp is delivered into the compartment 39 where it is combined withthe products entering said compartment 39 through the down-take pipes38.

The launder 37 is divided into compart ments, one compartment for eachspitzkasten, by fixed partitions 54 into which is inserted a rectangularremovable partition 55 so that the overflow of sub-froth together with asmall portion of gangue pulp from each lip 13 normally flows into itsrespective compartment formed by the partitions 54 and 55, and istransferred to the compartment 39 by each down-take pipe 38. However itsometimes happens that one down-take pipe will become clogged up, or onecell will become out of order so that, in this case the removablepartition 55 is removed so that the pulp is by-passed around the cellwhich is out of order, to the compartment in the launder 37 ofthe adjacent cell. The coarser particles contained in the pulp will settle tothe false bottom 15, and will not flow over the weir 51, so

that a sand hole 56 is provided in thefalse bottom 15, to allow thesecoarser particles to flowcinto the compartment 39,.where they willcombine with the other products introduced into said compartment.

It often happens in flotation plants, that the volume of'pulp variesfrom time to time, sothatan excessive overflow over the lip 13 in thefirst cell will soon cause a slope ping over the lips 13 of theremaining cells,

unless provision is made for lowering the head inthe remaining cells soas to relieve the overflow conditions.

we provide a weir gate 57 at the top of a as p r 1 65 isconnected tothis last mentioned arm,

small portion, of the gangue pulp flowingv ther end.

For this purpose weir 58 in the last cell. This weir gate is pivoted atone end to the wall 11 of the spitzkasten, by means of a hinge 59 andits position is controlled by a rod 60 pivoted to its The rod 60 isconnected to one arm of a bell crank lever 61 pivoted onthe framework ofthe machine, and the other arm of said lever is connected by a rod 62 toone arm of a bell crank lever 63 also pivoted on the frame-work of themachine. A spring 64: is connected to the other arm of the bell cranklever63 at one end, and is secured to the frame-work of the machine atthe other end, so that normally the weir gate 57 is in its lowermostposition. In order to actuate the bell crank lever 63, a cable or rodand extends to the feed end of the machine, where it is connected to onearm of a bell crank lever 66, pivoted to the machine. A rod 67 connectsthe other arm of the bell crank lever 66 to one arm of the bell cranklever 68, and the other arm of the lever 68 is connected by a rod 69 toa triangular shaped box 70 pivotally mounted by means of a pin 71 to thewalls 10 and 33 ofthe first cell, so as to be positioned approximatelyin the, path of the sub-froth and a small portion of gangue pulp whichflows downwardly into the launder 37 i This triangular shaped box 70 isopen at the top, and is provided at its lowermost corner with a port 72.This port 72 has a definite size, so that the sub-froth and a into saidbox 70 will drain out atia predeterniined rate of speed. However, whenthe flow of sub-froth and gangue-pulp becomes excessive, the box 70 willfill with material since the. port 72 will not then be 1 suflicient todrain the box, so that saidbox will move about its pivot 71thusactuating the system'of levers and links, thus causing the weir gate57 to be raised. When the weir gatej57 is thus raised a portion of thepulp in the last cell will flow out under the gate so as to lower thehead in the last cell, thus causing the head to lower in all the othercellsso as to relieve the overflow con ditions.

When the pulp thus flows out under the weir gate it flows downwardlyinto the com- 73, which conducts away the uselessgangue material. Afalse bottom 15 inthe last cell is provided with a pivotally mountedvalve 74 to which is connected a control rod 75,

'partment 39 of the lastcell, and then flows out of said compartmentthrough a tail race and the opening in said valve maybe ac-" curatelycontrolled by means of an adjust-V ing Wheel 76 threaded to receive theend of the rod 7 5,'and mounted on. a bracket 77 secured to the machine.The flow of the and is returned to the feed end of the machine. p r

In operation, the pulp which consists of crushed ore, water, and smallpercentages.

of oil and acid, is introduced into the agigangue material past thevalve 74 may thus tating chamber 16 on the first cell through the pipe18, and is thoroughly aeratedand agitated by the impeller 26. Theaerated pulp flows out through the port 20 into the spltzkasten and isdeflected downwardly toward the false bottom 15 of said spitzkasten bythe shield 27. The air bubblescontain ing the valuable minerals risetothe surface, and form a concentrate froth 42', which is supportedbythe sub-froth 43, in turn supported by the pulp 44. The coarser particles in the pulp, settle to the bottom of i the spitzkasten and flowthrough the hole 56 into the false bottom 15,- into the compartment 39.The major part of the pulp admitted to the spitzkastens overflowstheweir 51, and is combined with the other material in the compartment 39.The froth,

sub-froth and a small portion of the gangue pulp overflow the lip 13 ofthe spitzkasten where the aproncutter 45 cuts the concen- 28, while thelatter flows into the first middling launder 37. This apron cutter 45 is'trate froth from the sub-froth so that the" former flows into theconcentrate launder maintained in a definite position relative to thefroths 42 and 4:3 by the float 48 which floats on the surface of thepulp 44 so that a uniform cutting of the concentrate froth dling launder37 kastens.

The sub-froth flowing into the first midassesthrough the downtake pipe38 into t e compartment 39, where it joins the other products from thesand hole 56and the weir 51. The products combined in the compartment 39are drawn up through the pipe 50 into the agitating chamber 16 of thenext cell by the impeller in that compartment, where it is again aeratedand goes through the cycle of operations described in the first cell.The worthless gangue material which collects in the com artment 39 ofthe last cell, flows out of t e machine through the tail race 73, whilethe concentrate froth flows out of the concentrate launder 28 throughthe pipe 29, after which it is treated further to recover the valuableminerals.

If the pulp fed to the first agitating chamber varies involume from timeto time,

and an excessive overflow occurs at the lip .13 of the firstlpitzkasten, the overflow fills throu h the up the tria ar shaped tankdrained by the port which actuates the system of levers and linksillustrated in Fig. 11, so that the weir gate 57 in the last cell israised, thus causing pulp to flow out of the last cell under said weirgate, where it goes with the worthless gangue to the tail race 73. 'Ifthe overflow in the first middling launder 37 is so great that it cannotbe handled by the down-take pi 38, the excess overflow flows 52a 41 intothe middling launder 3 whichconducts the overflow through the pipe 34,,the elevator 35, the pipe 36 and the pipe 18,..baok into the agitatingchamber of the first cellof the machine. In case this method of handlingthe overflow is not sufficient, the excess flows over the removablepartition 55 into the first middling launder compartment of the nextcell. If any of the down-take pipes or other part of the cell become outof order or plugged up, the removable partition 55 may be removed sothat the excess pulp is by-passed around the cell which is out of orderto the next cell.

A flotation machine is thus provided in which a definite depth ofconcentrate froth is removed atall times regardless of the pulp level inthe spitzkasten, which may vary with variations in the volume of thepulp fed into the first spitzkasten. The machine is also provided withmeans for automatically equalizing and regulating the flow of pulpthrough the several cells so that the pulp level will be maintainedsubstantially constant. If one cell becomes out of order, the pulp maybe easily by-passed around this cell to the next cell in the series. Allmechanically operated Skimmers have been eliminated from the machine anda fewer number of flotation cells are necessar to produce a given soaration of minera s from the gangue. t may be desirable to use amechanical type of slow revolving skimmers in some cases which will bepositioned near the center of the spitzkastens of the machine, saidskimmers being adapted to further increase the discharge of concentratefroth over the froth cutter. The machine described and illustrated willmake a cleaner concentrate, a tailing containing a lower percentage ofvaluable minerals, and will have a lower consumption of oil, acid oralkali.

We would state in conclusion that while the illustrated exampleconstitutes a practical embodiment of our invention, we do not limitourselves precisely to the details herein illustrated, since manifestlythe same can be considerably varied without departing from the spirit ofthe invention, as defined in the appended claims.

Having thus described our invention we claim as new and desire to secureby Letters Patent:

1. In a flotation machine rovided with a container, having an over owlip, and a movably and automatically operated member associated withsaid container for uniformly separating the concentrate froth from thesub-froth, as said froths flow over said li regardless of the level ofthe pulp in said container.

2. A flotation machine provided with a container having an overflow lip,floating cutting means associated with said container adapted toseparate a uniform depth of concentrate froth from the sub-froth, assaid froths flow over said lip, regardless of the level of the pulp insaid container.

3. In a flotation machine, a plurality of containers arranged in series,and means associated with the first said containers adapted to release aquantity of pulp from the last of said containers when an excessivesupply of pulp is introduced into the first of said containers, so thatthe pulp level in said container is maintained substantially constant.

4. In a flotation machine, a plurality of containers arranged in series,a pivotally mounted weir gate associated with the last container in saidseries, and means associated with the first container for moving saidweir gate when an excessive quantity of pulp is introduced into thefirst container, so that the pulp level in said containers is maintainedsubstantially constant.

5. A device, as described in claim 4, characterized by a pivotallymounted box associated with the first of said containers, said box beingso positioned as to receive an excessive flow of material introducedinto said first container, there being a port formed substantiallyconstant.

adjacent the bottom ofsaid box adapted to I gate adapted to actuate saidgate when saidv box is moved about its pivot, so that the pulp level inthe containers is maintalned 6. in a flotation machine a' luralit ofcontainers arranged in series, each container being provided with anoverflow lip, means associated with each container adapted to aerate andagitate the pulp, and introduce "d aerated pulp into said containers, aenti'a'te launder 130Sil310118 l1011g11311d1- naliy of said containersadapted to receive the concentrate froth delivered from each container,aiirst middling launder adapted to receive the sub-froth and a portionof gangue pulp, delivered from the lip of said.

with each container adapted to allow the overflow of pulp therefrom, andmeans for combining said pulp overflowing said weir and. said sub-frothoverflowing "the lip of' said. containers and transferring said pulp andsaid sub-froth from one container to an adjacent container in the saidseries.

.7. A device as described in claim 6, char-' acterized by means forseparating a uniform depth of said concentrate froth from said sub-frothflowing over the lip of each conhaving an overflow edge, and a pivotedand automatically controlled member at said cdgeflfor separating theconcentrate froth" tainer, regardless of the level of the pulp in eachc'ontalner.

8. A device as described in claim 6, char- 7 acterized by means forIcy-passing the pulp around a container in said series, when saidcontainer is out of order.

9. A device as described in claim 6, charedge.

- ase acterized by a movable weir gate, associated with the lastcontainer in said series, and

means associated with tliefirst container insaid series adapted toactuate the said weir gate when an excessive quantity'ofpulp isintroduced into the first container of said series, so that thepulplevel in said container will be maintained substantially constant; I7

10. In a flotation machine, a container provided witha lip, means forintroducing an aerated and agitated pulp into said container so that aconcentrate froth and a. sub-froth are formed on the surface of sandpulp, means for causing the pulp to flow from. said container, a cutterapron pivotally associated with said container, and a floating memberassociated with said'cutter apron adapted to float on the surface ofsaid pulp, and maintain one edge of said cutter sition that a uniformdepth of concentrate froth will be separated'from the sub-frothregardless of thelevel of pulp in said containeia 11. A deviceasdescribed in claim 10,

characterized by means for combiningthe pul flowing from saidvcontainers with the sub-froth flowing over the lip of said containersand transferring said combined pulp and froth to an adjacent container.j

12. A device as described in claim 10, characterized by a fals bottompositioned in -said containers, means for combining said sub-froth withsaid pulp, and means for transferring said combined pulp. and subfrothto adjacent'containers.'

13.1n a flotation machine, a container from the sub-froth as they flowover said LEO DANIEL LYONS. CONRAD FRANCIS HOFF.

apron above said pulp surface in such a po-

